Evaluating whether perfSONAR-PS can be adapted to a system that enables energy-aware networking
by providing ease of discovery and access to domain-specific measurement data through which energy profiles
of network nodes can be constructed was comprised of the following research activities:

\begin{itemize}
	\item Familiarization with the software and code-base analysis
	\item Implementation of a test modef based on perfSONAR NC
\end{itemize}

\subsection{Familiarization with the perfSONAR software}

The findings of the activity have established that perfSONAR-PS is a good starting point for the GreenSONAR
project. It offers a centralized management resource through which one can represent measurements of various types
irregardles of the underlying metric. The software provices a resource through which the various underlying monitoring 
tools part of Multi-Domain Monitoring systems can be centralized into a single administrative entity. The software is capable of distributing various performance
metrics due to the usage of the NMWG XML data normalisation schema. Such a high degree of flexibility in terms of 
data representation is an interesting feature as advances in network standards such as \emph{802.3az} enable more 
granular energy measurements to be performed which would lead to modifications of the energy efficiency model calculation and thereby the underlying data that needs to be served.
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A drawback of the perfSONAR-PS and MDM systems is the usage of a SOAP XML protocol. The protocol presents a large amount of network overhead traffic. 
When requesting data from Measurement Archives that, for example, serve tuples of netwrok addresses and energy weights, the management overhead constitues for more than 99\% of network traffic.
The application of such systems in demanding environments such as data centers where Layer 2 facilities undergo numerous chages in order to optimize traffic would interfere with the rest of the switching plane.  


\subsection{Implementation of a test modef based on perfSONAR NC}
The test model aided the process of understanding the underlying functional dependencies of energy-aware networking. By developing a basic system that facilitates the distribution of energy and network statistics, we examined what other technologies need to be in place to influence the forwarding plane of network devices so that green paths can be constructed. The second important finding has to do with the fact that calculating \emph{absolute energy efficiency} is a computationally-expensive task the complexity of which grows proportionally to the number of switchports in a network.
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